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Identification, friend or foe ( IFF) is a combat identification system designed for command and control. It uses a transponder that listens for an interrogation signal and then sends a response that identifies the broadcaster. IFF systems usually use radar frequencies, but other electromagnetic frequencies, radio or infrared, may be used. [1]
Active noise control ( ANC ), also known as noise cancellation ( NC ), or active noise reduction ( ANR ), is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first. The concept was first developed in the late 1930s; later developmental work that began in the 1950s eventually resulted in ...
The aviation transponder interrogation modes are the standard formats of pulsed sequences from an interrogating Secondary Surveillance Radar (SSR) or similar Automatic Dependent Surveillance-Broadcast (ADS-B) system. The reply format is usually referred to as a "code" from a transponder, which is used to determine detailed information from a ...
Mode conversion occurs when a wave encounters an interface between materials of different impedances and the incident angle is not normal to the interface. [1] Thus, for example, if a longitudinal wave from a fluid (e.g., water or air) strikes a solid (e.g., steel plate), it is usually refracted and reflected as a function of the angle of ...
The Common Booster Core (CBC) was an American rocket stage, which was used on the Delta IV rocket as part of a modular rocket system. Delta IV rockets flying in the Medium and Medium+ configurations each used a single Common Booster Core as their first stage, while the Heavy configuration used three; one as the first stage and two as boosters. [1]
Elevated workplace or environmental noise can cause hearing impairment, tinnitus, hypertension, ischemic heart disease, annoyance, and sleep disturbance. [3] [4] Changes in the immune system and birth defects have been also attributed to noise exposure. [5] Although age-related health effects ( presbycusis) occur naturally with age, [6] in many ...
Modes of mechanical ventilation are one of the most important aspects of the usage of mechanical ventilation. The mode refers to the method of inspiratory support. In general, mode selection is based on clinician familiarity and institutional preferences, since there is a paucity of evidence indicating that the mode affects clinical outcome.
The Phrygian mode (pronounced / ˈfrɪdʒiən /) can refer to three different musical modes: the ancient Greek tonos or harmonia, sometimes called Phrygian, formed on a particular set of octave species or scales; the medieval Phrygian mode, and the modern conception of the Phrygian mode as a diatonic scale, based on the latter.